Carbonaceous bearing material



Mayv 26, 1936. xB. H. McQuEll-:R 2,041,896

CARBONAGEOUS BEARING MATERIAL Filed May 16, 1954 INVEN-roR l l roRNEY Y Patented May 26, y 1936 v 2,041,896 y oAaBoNAcEoUs BEARING MATERIAL Bert H. McQueer, Saint Marys, Pa., assigner to l Speer Carbon Company, a corporation ot `Pennsylvania l Application May 16, 1934, Seriall No. 726,010 401mm.- (cisos-uz) This invention relates to bearings and more es,- pecially to bearings consisting of, or containing, ycarbonaceous material, a portion of which is graphite, either natural or artificial.

In the drawing: l

Fig. 1 is a perspective view of a' clutch bearing cast-iron case.

Fig. 2 is a section on line 2-2 of Fig. 1.

This invention is capable of use in various bearings, but by way of example, it may be said that there are certain bearings in automobiles which l require special composition on account 0f the severe, service and infrequent lubrication. In such uses the usual bronze or Babbit metal bearv15 ings have not been satisfactory due chiefly to failure of the operator to keep the bearing properly lubricated. One form of. material used in these bearings has been amorphous carbon, either with or withi the binder. `To get better lubrication acon-` siderable amount of graphite has been added in some cases. 'Ihisof course lowered'the friction v .30 as desiredbut at the same time it softened the face of the bearing and caused excessivepwear.

The finished product of the prior art thus had graphite disseminated throughout in very fine particles surrounded by amorphous carbon. The latter was present in much greater amount to give the bearing strength and hardness. The resulting product was a practically homogeneous material of low permeability. Therefo-re the 1ubricant' such as oil, which' in a later step was soaked into the carbon bearings, couldv not freely pass out of the carbon body to the bearingsun face when in use. The prior art bearing composition was particularly likelyvto give high friction at the start before the material had warmed up and caused the oil to soak out sufliciently to form a film over the bearing surface. 'Due to this, bearings frequently got quite hotand often burnedout, particularly when new. If one attempted toincrease the permeability ofthe matrix the resulting product was too weak and the rate of wear too high;

`..II have carried out many experiments to overcome these and other difculties in carbon bearings and have found that the permeability of the carbon bearing may be controlled independently 'as to prevent their becoming broken down or disintegrated during their incorporation in the bearing structure.

In accordance with my new process I agglomer` ate graphiteinto a moreor less loose, permeable, structure and after solidifying this structure, break the material into the desired, sized particles f which should be the spot size hereinafter referred to. I then'incorporate these particles into the carbon matrix, taking care that the particles do not become encased in an impermeable shell of binder'carbon. I am thusable to control both the permeability of the bearing and the amount of graphite in the bearing face independent of the hardness and density of the general'bearing structure of matrix. v

As will appear later herein my bearing blocks 'when finished have Well defined graphite spots clearly contrasting with the carbonaceous matrix Icontaining them, whereas prior art bearing blocks 30 iine graphite our and hard pitch or other binder have the graphite in such fine form and so encased by baked-cn binder that the individual -graphite particles cannot be readily detected by j the eye.

- are as follows: o

The main body or .matrix may consist of any suitable amorphous carbon either with or without y graphite. I have secured excellent results by making the matrix of milled calcined coke and thoroughly mixed in heated condition. 'I'his of course lqueies the pitch. After cooling, lthe resulting mass is milled, say through mesh. This 60 mesh material may fer convenience be designated as the A mix and constitutes the 0 in heated condition as will bind the graphite par- 55 Sii 2 abaisse ticles together without encasing them suiliciently with pitch to seriously reduce the permeability,

After cooling, the mass is milled through 20 to" 40 mesh. I'hat is, the resulting particles are no l convenience. While I have successfully used the- .*B mix as just described, with the desired proportion of the A mix, I prefer to further treatL the B mix" by forming 'it into blocks, bake to about 1500* F; and'then mill through Z0 to 40 mesh. This treatment makes the particles more permeable and otherwise improves the lubricating quality of the spots. In fact, by baking to this or higher temperature the spots are rendered more porous than the carbon matrix.

I have mixed the A and 2B mixes in various proportions and `have produced successful bearings therefrom. From 2% to 15% of the B mix and 98% to 85% of the A mix give excellent results. The most suitable proportion appears to be oi' the i3 mix and 95% of the A mix.

Ihese two mixes of the selected proportion are mixed cold and molded, extruded or otherwise formed into the desired shape of bearing and baked to preferably 2200 F. in about seven days, though a lower baking temperature gives good results also, after which they may be shaped or machined to size when desired.

I have also obtained excellent results by graphitizing the material constituting the E mix before it is milled to lnal spot" condition. Also artificial graphite of the desired spot size may be used for the final B mist.

In the drawing the bearing block i is made as described above and is forced into the cast-iron case 2 while the latter is in heated condition. This iron case is not part oi the invention and any other means for holding the carbon bloei: in position may be used. On cooling, the carbonaceous'block is firmly held inplace in the case. The assembly may then be soaked in oil, hot petrolatum or other lubricant material to aid the graphite in keeping the bearing lubricated. The relatively large spots of graphite aid in this absorptlon of lubricant and exude it during use. The

spots therefore doubly aiect the lubricating qualities of the bearing. They increase the permeabilityand increase the surface of the graphite in contact with the journal shaft. In use oil may be applied through the opening 3 which may have Athe usual cup or other oil receptacle.

different forms and in many different uses. 'I'he Y invention is therefore not limited to any particular shape or use. i

The invention is-also not to be limited to the spot size given in the specic example. Other sizes may be used. The invention is not limited to gphite as a lubricating material since talc or other solid lubricants may be substituted. 'I'he novel feature is in using lubricating particles that are materially larger than the particles of the matrix and which are more permeable than.

the baked matrix material. In the prior art 'bearing material the carbon material of the matrix has been a Very ne iiour and the graphite mixed therewith has also been of ne size. Speciiically, the prior practice has been to mill the amorphous carbon and graphite as a single mix to 90% through 200 mesh.

Having described my invention, what I claim is:

l. A bearing material adapted to hold lubricating fluid, consisting of iine particles of graphite and amorphous carbon, porous spots of graphite materially larger than said particles, said spots consisting of graphite powder held together by a porous graphitized binder, and a porous amorphous carbon binder holding said particles and said spots together whereby the said spots can absorb lubricating fluid when the bearing material is in contact therewith.

2. A bearing material adapted to hold lubricatingr iiuid, consisting of ne particles of graphite and amorphous carbon, a substantial amount of the graphite particles being located together in spots free of said amorphous carbon particles and being held together by a porous binder, and a porous amorphous carbon binder holding said particles and spots together whereby said graphite spots can absorb lubricating iiuid when the bearing material is in contact therewith.

A bearing material adapted to hold lubricating iluid, consisting of iine particles of amorphous carbon, spots of porous graphite materially larger than said particles, said spots consisting oi graphite powder held together by a porous binder, and a porous amorphous carbon binder holding said particles and said spots together whereby the said spots can readily absorb lubricating fluid when the` bearing material is in contact therewith.

fi. A bearing material capable of absorbing lubricatingf fluid consisting of a porous matrix and porous-spots or graphite interspersed therein and constituting not more than 15% of the matrix,

said matrix consisting of amorphous carbon particles and a carbonaceous binder, the graphite spots being materially larger than said particles and having a porosity substantially equal to that of the matrix.

BERT H. MCQUEER. 

